Process for preparing bisphenol-A

Abstract

In the preparation of bisphenol-A by condensation of phenol with acetone in the presence of an acidic ion-exchange resin catalyst, pretreatment of the catalyst to render it anhydrous comprises two steps to minimize resin degradation. In the first step, from 25 to 90 percent by weight of the resin associated water is removed by vaporization, and in the second step dehydration is completed by saturating the partially dehydrated catalyst with phenol. The advantage of the improvement in the process resides in a more efficient drying, requiring less time and minimal degradation of the resin structure.

In the claims: 
     
       1. A process for the preparation of bisphenol-A, which comprises; providing a hydrated acidic ion-exchange resin catalyst for catalyzing the condensation of phenol with acetone;   vaporizing a portion of the water associated with the hydrated catalyst;   separating sufficient of the water vapor from the catalyst to remove from 25 to 90 percent by weight of said water, whereby a partially dehydrated catalyst is obtained; and   contacting the partially dehydrated catalyst with phenol so as to remove additional water from the catalyst until the water content of the effluent phenol contains less than about 4 weight percent water; and   condensing phenol and acetone in a reaction zone at a temperature within the range of from 40° to 95° C., in the presence of the dehydrated catalyst.   
     
     
       2. A process of claim 1 wherein the resin catalyst is gellular. 
     
     
       3. A process of claim 1 wherein the level of dehydration is brought to less than about 1 weight percent water.